Field of the Invention
The present invention relates to a zoom lens and an image pickup apparatus including the same, and is advantageously applicable to an image pickup apparatus that uses an image pickup element, such as a video camera, an electronic still camera, a broadcasting camera, or a monitoring camera, or an image pickup apparatus such as a silver-halide film camera.
Description of the Related Art
A zoom lens for use in an image pickup apparatus is desired to be compact, have a high zoom ratio, and have a high resolving power over the entire zoom range. As a zoom lens for achieving a high zoom ratio, a positive-lead type zoom lens is known, in which a lens unit having a positive refractive power is placed at a position closest to an object.
Japanese Patent Application Laid-Open No. H07-270684 discloses a four-unit zoom lens including, in order from an object side to an image side, first to fourth lens units having positive, negative, positive, and positive refractive powers, respectively.
Japanese Patent Application Laid-Open No. 2007-178598 discloses a five-unit zoom lens including, in order from the object side to the image side, first to fifth lens units having positive, negative, positive, positive, and positive refractive powers, respectively. Japanese Patent Application Laid-Open No. 2012-128116 discloses a five-unit zoom lens including, in order from the object side to the image side, first to fifth lens units having positive, negative, positive, positive, and negative refractive powers, respectively.
Meanwhile, Japanese Patent Application Laid-Open Nos. 2007-248952 and 2010-48855 each disclose a zoom lens in which a reflection member configured to bend the optical axis of the zoom lens is placed on an optical path with an aim to reduce the thickness of an image pickup apparatus.
For a zoom lens having such a reflection member, it is important to appropriately set lens configurations, the position of the reflection member, and so on.
For example, placing the reflection member in a front part of a lens system reduces the depth dimension of the lens system. In this case, however, large space is necessary in the image side of the reflection member to place multiple lens units that move for zooming in a direction perpendicular to the optical axis of incident light on the lens system, and the width dimension of the camera tends to increase to create such large space. Not only the width dimension, but also the height dimension of the camera tends to increase due to the necessity of creating space in the height direction as well.